GENERATOR INTERCONNECTION FACILITIES STUDY FOR DAN RIVER STEAM PLANT COMBINED CYCLE PROJECT With BIOMASS CONVERSION IN PLACE ROCKINGHAM COUNTY, NC

Transcription

1 GENERATOR INTERCONNECTION FACILITIES STUDY FOR DAN RIVER STEAM PLANT COMBINED CYCLE PROJECT With BIOMASS CONVERSION IN PLACE ROCKINGHAM COUNTY, NC Prepared by: Fred Kimsey Geno Price Roger Hurst Steve Mc Clure

2 TABLE OF CONTENTS INTRODUCTION... 3 BASELINE ASSUMPTIONS... 4 DUKE INTERCONNECTION FACILITIES... 6 I. COST ESTIMATES... 6 II. WORK SCOPE DESCRIPTION FOR INTERCONNECTION FACILITIES... 6 A. General B. Short Circuit Withstand Capability C. Equipment Ratings D. Insulation Requirements E. Metering APPENDIX A Proposed One Line for Dan River Combined Cycle 100 KV Substation Proposed Electrical One Line APPENDIX B Interconnection Facilities Milestone Schedule Requirements Page 2 of 18

3 INTRODUCTION Generator Interconnection Facility Study Results NOTE: THIS FACILITY STUDY IS A REISSUE OF THE PREVIOUSLY ISSUED STUDY WHICH SUPPORTED THE INTERCONNECTION OF A GAS FIRED COMBINED CYLCE FACILITY. THE PREVIOUS STUDY HAD ASSUMED ALL LOCAL GENERATION WOULD BE RETIRED HOWEVER THAT DECISION WAS REVERSED TO ACCOMMODATE CONVERSION OF ONE UNIT TO BIOMASS. THIS DECISION DID NOT MATERIALLY IMPACT THE RESULTS OF THE PREVIOIUSLY ISSUED FACILITY STUDY. THIS STUDY IS BEING ISSUED FOR RECORD PURPOSES ONLY. Duke Energy Generation ( Customer ) has proposed to install additional generation in the electric transmission control area owned and operated by Duke Energy Corporation ( Duke ). The Customer s requested interconnection point is at Duke s Dan River Steam Plant located in Rockingham County, NC. The Customer s proposed total facility generating capacity is 727 MW Summer. The generation represents a two on one combined gas facility and Dan River Unit 3 (106MW) retrofitted for biomass operation. The targeted commercial operation date is June 1, At the request of the Customer, Duke performed and delivered to the Customer a Generation Interconnection Study ( GI Study ). This GI Study, dated summarized all thermal, short circuit, stability, and reactive capability constraints resulting from the interconnection of the Customer s proposed generating facility. This Facility Study quantifies the work scope and cost associated with addressing both the Customer Interconnection and the required Network Modifications to address the identified constraints. For the purpose of this Facility Study the Interconnection Facilities are defined as those facilities linking the Customer s generation with the Transmission Owner s interconnection switchyard. It shall consist of facilities owned and operated by both Duke and the Customer. The Interconnection Point ( IP ) shall be defined as the location where ownership changes between the Customer and Duke. The IP shall be located at the terminal pad of the line disconnect switch where the Customer s Interconnection Facilities enters and connects to the interconnection substation. Appendix A provides a representative schematic of the 100 KV portion of the substation and indicates more precisely the location of the IP. Responsibilities for the development, construction, and maintenance of the Interconnection Facilities are addressed later in this document. Duke s Interconnection Facilities are addressed separately from the Network Modifications in this Facility Study. Network Modifications are all of those system changes necessary to address constraining network elements as identified by thermal, fault current, and stability studies. Specific scope for Duke s Interconnection Facilities and the required Network Modifications are addressed in subsequent sections of this document. Page 3 of 18

4 BASELINE ASSUMPTIONS Duke s facilities are based on application of industry standard equipment. As such the total capability may accommodate energy flows greater than those assumed to be present in the Generation Interconnection Request. In the event the Customer decides to interconnect an additional increment of capacity, a new Generation Interconnection Request will be required to evaluate the impacts. Any constraints that may result will be identified as part of the new study request. The following assumptions have been used to establish the project scope and cost estimate for the identified facilities. 1. This Facility Study is premised on Duke providing turnkey design and installation of all Transmission Owner s Interconnection Facilities associated with a 100KV interconnection of the Customer. 2. The interconnection voltage will be at a nominal voltage of 100KV. 3. The existing CTs and two coal fired units will be permanently removed from service prior to summer The third coal fired unit will be converted to biomass fuel. 4. The area identified as the interconnection substation yard shall be kept free of materials and equipment associated with the power island. This shall include but not be limited to fire protection piping, water and sewer lines, duct bank systems, fuel supply lines, structures and other electrical equipment. Only exception to this shall be any piping and catch basins which may be required to effectively accommodate storm water run off. Location of any subsurface drain lines or catch basins shall be mutually agreed upon between Duke and the customer. 5. The Customer shall install Out of Step Relay Protection on their generators. 6. The Customer and Duke have mutually agreed to establish the interconnection point at the line terminal which lies within the internal boundaries of the Dan River CT Interconnecting Switchyard. The biomass fired unit will remain connected via the existing bus line associated with the converted generator. 7. Duke will design, construct, own and operate all of Duke s Interconnection Facilities. Duke s Interconnection Facilities are defined as the 100KV interconnection substation.. The Customer s interconnection facilities are the three 100KV bus lines extending between the generator step up transformers and Duke s Interconnection Facilities. A one line representation of the 100KV Substation is provided in Appendix A. 8. The biomass generating unit shall be connected to the grid via the exiting Unit 3 bus line. Page 4 of 18

5 9. The IP shall be the terminal pad of the bus line disconnects located in proximity to the bus line catch off structure. Refer to the Appendix A for further clarity around where this point occurs. 10. Any required outages necessary to support construction of Duke Interconnection Facilities and/or Network Modifications must occur during a spring or fall time frame. If an outage of sufficient duration cannot be obtained to support any of the required construction activity, temporary facilities may have to be constructed to maintain integrity of grid. No provisions have been made for temporary work in the estimates provided herein. 11. The protection schemes installed by Duke at its Interconnection Facility are intended to protect Duke s network from the Customer s Facilities. 12. Electrical protection schemes for the bus lines interconnecting the plant to the substation shall be the responsibility of the Customer. The bus-line protection scheme must include separate primary and secondary schemes whose operation shall be coordinated with the Interconnection Substation s protection schemes. 13. Any required communications and control circuits between Duke s facilities and the Customer s Facility shall be the responsibility of the Customer. 14. All relay settings for the breakers at Duke s Facility will be the responsibility of Duke. 15. Duke maintains all rights for the commission testing of any substation facility that it owns. Duke reserves the right to inspect and witness commission testing of any switchyard and transmission line facility constructed on behalf of the Customer for the purpose of interconnecting to Duke s transmission grid. 16. Auxiliary power requirements for the Customer Facility must be metered. The Customer is allowed to self supply when generating however when generation is not on line it must be properly accounted for and billed. 17. All telemetry circuits that provide the generation plant operational and billing data to Duke s System Operations Center (SOC) will be the responsibility of the Customer. 18. All estimates prepared for this Facility Study are considered to be good faith estimates represented in present day dollars as of the date of the Study. The estimates are further premised on being able to perform work during normal business hours with minimum overtime or weekend work. The Customer will be responsible for all actual costs. 19. The Customer s financial responsibilities for Duke s regulated facilities will be determined in accordance with the Duke s Open Access Transmission Tariff ( OATT ) in effect at the time of design and construction. 20. All schedules provided herein are provided as a guideline for planning purposes. Detailed work planning will not begin on any facilities until the appropriate Large Generator Page 5 of 18

6 Interconnection Agreement ( LGIA ) has been executed, appropriate monies tendered, and credit securities provided. 21. Upon receipt of the Customer s notice to proceed, Duke will develop appropriate work plans and initiate certain design and procurement activities. The Customer will be responsible for all costs incurred by Duke associated with those efforts. Should the Customer reconsider its decision to proceed or determine it must suspend the project for some period of time this will not relieve the Customer of financial responsibility for costs or obligations incurred by Duke in support of the Customer s project. DUKE INTERCONNECTION FACILITIES I. COST ESTIMATES As per the requirements of the Tariff, the following good faith estimate is provided. This estimate assumes no temporary facilities will be required to support the construction effort. Definition of the scope associated with each of these can be found in the following sections. Ref.# Table 1 Facility Total Estimated Cost A Dan River CCCT Interconnect Yard $3,902,015 B Relay, Controls And Communication Note 1 0 C Motley 100KV Line Rebuild Motley Tie To Interconnect Yard $ 872,858 D Motley 100KV Line Rebuild Interconnect Yard To Dan River $ 1,558,298 E Ridgeway 138KV & Meadow Summit #2 44KV Lines Relocation $ 1,252,178 F Motley Line Terminal Upgrade at Dan River $ 1,327,062 G Motley Line Terminal Upgrade at Motley Tie $ 233,015 H Motley Line Relay Terminal Upgrade at Meadow Green Retail $ 92,769 Note 1 Cost for Relay & Controls incorporated into Line A Total $ 9,238,195 II. WORK SCOPE DESCRIPTION FOR INTERCONNECTION FACILITIES A. Dan River CCCT Interconnect Yard To interconnect the Customer s facility a new 100KV switch yard will be constructed in front of the proposed power island. The new switch yard shall comply with all of Duke Energy s Substation Engineering Standards. To interconnect this yard to the grid the double circuit Motley 100KV lines will be folded into the proposed yard. In addition the Mayo Bl and White Circuit terminals currently in the Dan River Steam Station Switch yard will be Page 6 of 18

7 relocated to the new switch yard. By relocating the Mayo lines a more cost effective solution is realized since less of the main bus in the Dan River Steam Station switch yard will have to be rebuilt and the existing Mayo Black breaker replacement will be addressed through the relocation effort. The new yard will leverage a single breaker double bus arrangement. Each line and each generator shall be selective between the 2 busses. Under normal operation 2 generators would be tied to one bus and the 3rd generator to the 2nd bus. The switch yard will require the installation of eight 121KV, 2000A, and two121kv, 3000 amp circuit breakers along with the associated compliment of isolating switches. The current plan will require the development of a switchyard having a footprint approximately 350 feet wide by 200 feet deep to accommodate all required structures, foundations, equipment, grounding, control house, protection and controls, and lighting. No consideration of spill containment efforts have been incorporated into the overall design effort because none of the proposed equipment will contain any oil. Each generator bus line will terminate into its respective terminal which will include a gas circuit breaker and associated switches and protection and controls. The bus line breakers shall serve as the high side protective devices to each units generator step up transformer. Revenue grade CT s and meters will be supplied at each bus line breaker to appropriately meter the energy crossing the interconnection point. Due to existing available fault current all equipment shall be rated to accommodate a fault duty up to 63 ika. A proposed one line schematic is included in Appendix A for clarity. B. Relay, Controls and Communication Appropriate protective relaying will be installed to allow for safe and reliable operation of the system. Close coordination of these schemes will be required with the power island to adequately cover all protective zones. No provisions are made to allow for communications of generator specific information between the Customer s facility and the existing control room of the currently in place fossil fueled generators, nor the Control area s System Operations Center. A pre-fabricated relay house will be installed in the new Interconnection Yard to house all the relay protection and communications equipment. The primary line terminal protective relaying at the Interconnection Yard for the Motley lines will consist of line current differential relaying, either an SEL-311L or an RFL GARD8000 relay for each line. The communications between the line current differential relays will be via fiber optic cable. The secondary line terminal protective relaying at the Interconnection Yard for the Motley lines will consist of an SEL-351 relay on each line for directional over current protection, and will also contain the breaker failure protection. Due to the short length of the bus lines, and no Circuit Breakers on the high side of the GSU s in the Transformer Yard, the bus lines will be integrated into their individual GSU transformer Page 7 of 18

8 differential protection scheme. Each bus line Circuit Breaker at the Interconnection Yard will have an SEL-351 for breaker failure protection. SEL-2032 Communication Processors will be utilized for local station alarms, relay data, and SCADA functions to the TCC. Instrument Voltage Transformers will be installed on all three phases of both 100KV buses of the Interconnection Yard for relay input voltage and synchronism. Instrument Capacitor Voltage Transformers will be installed on Z phase of the line side of the four line terminal breakers for synchronism. The control power for the electrical equipment will be one 130 volt, 60 cell, flooded lead acid battery bank. All DC power, control, and CT cables to be 1000V shielded. All AC power cables to be 2000V shielded. C. Motley 100KV Line Rebuild Motley Tie To CCCT Interconnect Yard The rebuild and fold-in of the Motley 100KV line from Motley Tie to the new Dan River CCCT interconnect yard will require removal of all existing towers and conductors and installation of new structures and conductors. Three new double circuit angle/dead-end towers and two new double circuit tangent towers will be installed. The new conductors will consist of a two conductor bundle configuration of 556 ACSR. The two overhead ground wires will be 3/8 EHS. The fold-in section of the line will require new dedicated right-ofway free of any facilities including but not limited to roadways, distribution lines and any other utilities. D. Motley 100KV Line Rebuild CCCT Interconnect Yard To Dan River Switch Yard The rebuild and fold-in of the Motley 100KV line from the new Dan River CCCT interconnect yard to the existing Dan River switch yard will require removal of all existing towers and conductors and installation of new structures and conductors. Four new double circuit angle/dead-end towers and two new double circuit tangent towers will be installed. The new conductors will consist of a two conductor bundle configuration of 1272 ACSR. One overhead ground wire will be 3/8 EHS and one fiber optic ground wire will be 1/2 EHS. The fold-in section of the line will require new dedicated right-of-way free of any facilities including but not limited to roadways, distribution lines and any other utilities. E. Ridgeway 138KV & Meadow Summit #2 44KV Lines Relocation The relocation of the Ridgeway 138KV and Meadow Summit #2 44KV lines, attached to common double circuit structures, will require approximately 0.4 mile of new dedicated rightof-way free of any facilities including but not limited to roadways, distribution lines and any other utilities. All structures and conductors in the proposed relocation section will be Page 8 of 18

9 removed. Three new double circuit angle/dead-end towers and two new double circuit tangent towers will be installed on the centerline of the new right-of-way. The new conductors will be 556 ACSR and the new overhead ground wires will be 3/8 EHS. F. Motley Line Terminal Upgrade at Dan River The Motley 100KV lines from the Interconnecting Substation to Dan River Steam Substation will be rebuilt using ACSR. In conjunction with upgrading this line, the terminals at Dan River Steam Substation must thermally coordinate with the proposed line conductors. It will be necessary to upgrade the double circuit line terminal at Dan River to meet the capacity of the bundled 1272 ACSR. Both Motley Black and White terminals will require the following upgrades. Replace the line disconnects with new disconnects having a capacity of 3000 Amp. Replace the 1600 amp breakers with 3000 Amp gas breakers. Install new concrete bases for the breakers. Currently the conductors at Dan River consist of copper material. New conductor drops to the breaker will be KCM AAC. The 2 Copper pipe will be replaced with 5 Al pipe. Over-head switches will be special order and upgraded to 3000 Amp. The terminal bus will be 5"Al EHPS up to the stacked red and yellow main buses. Half of the main Red and Yellow buses will be upgraded to 5 Al pipe. Install conduit as necessary and pulling the new fiber optic cable from the termination box near the 100KV Motley lines tower in the switchyard into one of the new Motley line relay panels in the plant. The electrical upgrades will consist of the following: Replace the existing Motley Black line panel C4 with one SEL-311L line current differential for the primary and one SEL-351 directional over current for the secondary relaying. Replace the existing Motley White line panel C9 with the same relaying as the Black line. The communications for the SEL311L relays will be via fiber optic cable. G. Motley Lines Terminal Upgrades at Motley Tie The Motley 100KV lines from the Interconnecting Substation to Motley Tie will be rebuilt using ACSR. In conjunction with upgrading this line, the terminals at Dan River Steam Substation must thermally coordinate with the proposed line conductors. It will be necessary to upgrade the double circuit line terminal at Dan River to meet the capacity of the bundled 556 ACSR. Both Motley Black and White terminals are adequate at 2000 amp to operate with the increased capacity of the line. However, due to relaying changes, 6 free standing Instrument Current Transformers will need to be installed on each phase of the line entering and exiting. Civil requirements will be to install 6 lattice stands to support the 100KV CT's. Replace the existing two 100KV line Capacitor Voltage Transformers. The relaying upgrades will consist of installing SEL-311L relays on the Motley Black and Motley White lines. Install a new communication panel with an SEL-351S-6 for the HT/Swapover and SEL Fiber Optic cable will be used for the communication. Page 9 of 18

10 H. Motley Lines Relay Upgrades at Meadow Green Retail Replace the existing Motley Black line panel with one SEL-311L line current differential for the primary and one SEL-351 directional over current for the secondary relaying. Replace the existing Motley White line panel with the same relaying as the Black line. The communications for the SEL311L relays will be via fiber optic cable. Install a SEL-351S-6 and SEL-551 on the Tap line to Miller Brewing. Install a new 100KV Bus Diff Page 10 of 18

11 REQUIRED NETWORK MODIFICATIONS The GI Study identified the constraining system elements resulting from the addition of the Customer s generation. Table 2 defines the required modifications and provides the associated costs. Estimated costs or Network Modifications TABLE 2 Ref # Required Network Modification Over Dutied 100KV Breakers at Dan River Steam Substation Motley Black and Mayo Black Alamance 100KV Line Rebuild (Burlington Tap to Mebane Tie 4.61 miles 2 cond 795 ACSR) Alamance 100KV Line Terminals at Glen Raven Main Substation Alamance 100KV Line Terminals at Mebane Tie Substation Elon 100KV Line Rebuild Reidsville Tap To Glenn Raven (18.68 mi) Elon 100KV Line Rebuild Sadler Tie To Reidsville Tap Elon 100KV Line Terminals at Glen Raven Main Substation Elon 100KV Line Terminals at Sadler Tie Substation Elon 100KV Line Terminals (and Bus) at Brandy Tap Bent Alamance 100 kv Line -Burlington Main Tap Bent Upgrade Estimated Cost $ 0 $ 4,708,126 $ 620,204 $ 968,168 $ 21,765,347 $ 3,377,555 $ 578,939 $ 561,313 $ 179,023 $ 80,800 TOTAL $ 32,839,475 I. Work Scopes for Required Network Modifications. 1. Overdutied Breaker Replacement With the addition of Dan River Combined Cycle Facility the available fault current as seen at the Dan River Steam Station 100KVsubstation bus will increase. Fault studies indicate that the existing Mayo Black and the Motley Black 100KV line breakers which are rated 43 ika and 44 ika respectively would be subject to interrupting current levels greater than their respective interrupting capability. The Motley Black breaker replacement will have to be replaced to thermally coordinate with the upgrading of the line segment between Dan River Steam Plant Station and the Page 11 of 18

12 Customer s new interconnection yard therefore the replacement cost of that breaker has been excluded from the overdutied breaker condition. The replacement of the Mayo Black breaker will not be required in the Dan River Steam Station switch yard because the line terminal is being relocated to the new interconnection switch yard. 2.Alamance 100 kv Line Rebuild Rebuild of 4.62 miles of the Alamance 100KV lines from Burlington Tap to Mebane Tie is required. This effort requires the removal of all existing structures and conductors. Six new double circuit 1EWL angle/dead-end towers and thirty new double circuit 1AWL tangent towers will be installed on the centerline of the existing right-of-way. Each line shall be reconductored using a two conductor bundle 795 kcmil ACSR configuration. Two 3/8 EHS overhead ground wires will be installed. 3.Alamance 100 kv Line Terminal at Glen Raven Main Substation In conjunction with upgrading the Alamance 100 kv line, the line terminals must thermally coordinate with the proposed line conductors. It will be necessary to upgrade the double circuit line terminal at Glen Raven Main. This will require the following Replacement of the 1-1/2 pipe conductor with 2-1/2 al pipe Upgrade all single 2000 KCM Aluminum conductors with two 2000 KCM Aluminum Upgrade the 1200 amp disconnects switches and OH gang switch will to 2000 A. Replace 2000 A line breakers with 3000 A equipment. Replace steel angle bus with 2-1/2 Aluminum pipe. Replace the relaying on the 100KV Alamance Black and White lines with SEL relays. Install a Coupling Capacitor Voltage Transformer (CCVT) on the line side of "Z" phase of both Alamance lines for synchronizing. Install a PLC breaker annunciator in the new gas breakers. Replace the station service AC cable in both Alamance breakers with cable to accommodate a single phase, 240 volt, 50 amp circuit. 4.Alamance 100 kv Line Terminal at Mebane Tie Substation In conjunction with upgrading the Alamance 100KV line, the line terminals at Mebane Tie must thermally coordinate with the proposed line conductors. It will be necessary to upgrade the double circuit line terminal at Mebane Tie. To meet the capacity of the bundled 795ACSR, the line will require the following upgrades: Replace the station switch outriggers with 2-1/2 aluminum. Page 12 of 18

13 Upgrade the 1200 A disconnect switches and the OH gang switch with 2000 A devices. Replace the current 1600 A line breakers 3000 A equipment. Replace conductor drops to the breakers and the between busses with two 2000 KCM Aluminum conductors. Replace the all angle bus with two 3-1/4 Aluminum angle. Reconductor the main Red and Yellow busses. New bus shall be two 3-1/4 aluminum angle. Upgrade the existing Bus Junction breaker terminal to 3000 A to thermally coordinate with the main bus. This includes replacement of the bus junction breaker. Replace the relaying on the 100KV Alamance Black and White lines with SEL relays. Replace the 100KV Bus Differential and Bus Junction relay panel with SBD 87B relays. Install a Coupling Capacitor Voltage Transformer (CCVT) on the line side of "Z" phase of both Alamance lines for synchronizing scheme. Install a PLC breaker annunciator in the new gas breakers. Replace the station service AC cable in both Alamance breakers and the Bus Junction breaker with cable to accommodate a single phase, 240 volt, 50 amp circuit. 5. Elon 100 kv Line Rebuild Reidsville Tap To Glenn Raven The rebuild of the Elon 100KV line from Reidsville Tap to Glenn Raven Main consists of removal of all existing structures and conductors. Twenty new double circuit 1EWL angle/dead-end towers and one hundred thirty new double circuit 1AWL tangent towers will be installed on the centerline of the existing right-of-way. The new conductors will consist of a two conductor bundle configuration of 954 ACSR. The two overhead ground wires will be 3/8 EHS. 6. Elon 100KV Line Rebuild Sadler Tie To Reidsville Tap The rebuild of the Elon 100KV line from Sadler Tie to Reidsville Tap consists of removal of all existing structures and conductors. Four new double circuit 1EWL angle/dead-end towers and twenty new double circuit 1AWL tangent towers will be installed on the centerline of the existing right-of-way. The new conductors will consist of a two conductor bundle configuration of 954 ACSR. The two overhead ground wires will be 3/8 EHS. 7. Elon 100 kv Line Terminal at Glen Raven Main Substation In conjunction with the Elon 100 kv Line Rebuilds the terminals associated with the line must be upgraded to thermally coordinate with the line. This requires rebuild of both line terminals at Glen Raven Main Substation to 3000 A. Work scope will consist of the following: Upgrade the 1-1/2" Al pipe to 2-1/2" Al. Upgrade the 1200 A disconnects to 3000 A disconnects. Replace the 1600 A breakers with 3000 A units. Page 13 of 18

14 Replace the 1200 A OH gangs with 3000 A gangs. Upgrade the wire drops to two 2000 kcmil Al. Replace the relaying on the 100KV Elon Black and White lines with SEL relays. Install a Coupling Capacitor Voltage Transformer (CCVT) on the line side of "Z" phase on both lines. Install a PLC breaker annunciator in both new gas breakers. Replace the station service AC cable in both Elon breakers with cable to accommodate a single phase, 240 volt, 50 amp circuit. 8. Elon 100 kv Line Terminal at Sadler Tie Substation In conjunction with the Elon 100 kv Line Rebuild, the terminals associated with the line must be upgraded to thermally coordinate with the line. This requires rebuild of both line terminals at Sadler Tie Substation to 3000 A. Work scope will consist of the following: All bus and wire drops must be converted to two 2000 kcmil AAC. Replace six sets of 1200 Amp disconnects will be to 3000 amp. Replace the 1250 kcmil AAC strain bus with two 2000 kcmil AAC. Replace the 100 kv Black and White line breakers with 3000 amp breakers. This will require installation of new concrete foundations. Replace the relaying on the 100KV Elon Black and White lines with SEL relays. Install a Coupling Capacitor Voltage Transformer (CCVT) on the line side of "Z" phase on both lines for synchronizing schemes. Install a PLC breaker annunciator in both new gas breakers. Replace the station service AC cable in both Elon breakers with cable to accommodate a single phase, 240 volt, 50 amp circuit. 9. Elon 100 kv Line Terminals (and bus) Brandy Tap Bent With the upgrade of the Elon 100kV Black and White lines, all series conducting elements at Brandy Tap bent must be upgraded to effectively thermally coordinate with the line rating. This will require the following: Re place the 1200 A disconnects with 3000 A disconnects Replace the 1-1/2 Al pipe will be upgraded to kcm al. Replace the 2-1/2 steel and aluminum angle bus with to 2 1/2/ Al pipe. 10. Alamance Line Burlington Main Tap Bent Upgrade With the reconductor effort of the Alamance 100 kv Lines between Burlington Main Tap and Mebane Tie all current carrying elements must be upgraded at the tap bent to thermally coordinate with the upgraded 2 conductor bundled 795 kcmil ACSR. This will require replacement of switches, bus drops and bus work. SCHEDULE FOR INTERCONNECTION FACILITIES Page 14 of 18

15 Appendix B provides definition of critical milestones necessary to support the requested in service date. In accordance with Duke s OATT, failure to adhere to the prescribed milestones may result in loss of queue position and suspension of the project. Should that event occur, the Customer will remain liable for all costs incurred to date plus any additional cost which might have to be incurred to return impacted facilities to a reasonable condition and service. A more detailed work plan and project schedule will be developed once an authorization to proceed is received. This authorization shall take the form of an executed LGIA backed with an appropriate security equal in amount to the commitments Duke must make to take the project forward. NOTE: No provisions have been made for the construction of any temporary facilities that might have to be constructed should outages not be granted. CONNECTION REQUIREMENTS A. General General requirements as defined in IEEE IEEE Guide for the Interconnection of User-owned Substations to Electric Utilities shall apply to this facility. This Facility Study document is intended to provide a basic scope definition of facilities on which Duke has based its facility study and cost estimates. It shall serve as the basis for the facilities that Duke proposes to design, build, and operate in connection with interconnection of Customer generation in the Rowan County NC area. Should there be differences between this document and IEEE 1190, this document shall take precedence. All Facilities installed by Customer and connected to Duke's Network shall comply with Facility Connection Requirements dated December 6, This document shall supplement those requirements where necessary. B. Short Circuit Withstand Capability Duke assumes no responsibility for appropriately sizing the short circuit withstand capability of any equipment installed on the Customer s Side of the Interconnection Interface. DUKE will provide upon request the maximum available short circuit current based on its current models. The Customer however must realize that significant numbers of new generation requests are constantly being received all of which will add to the available short circuit current. The Customer will need to exercise extreme care in appropriately sizing its equipment while providing for reasonable margin for future increases in available short circuit current. Duke bears no responsibility in the sizing decision. Available short circuit currents on Duke s system can be in excess of 80KA depending upon location and voltage. C. Equipment Ratings Prior to finalizing specification of equipment necessary to interconnect to the power grid, the Customer shall consult with Duke to establish the required ratings necessary to reliably interconnect and provide the expected Voltage and Var support as defined in the Page 15 of 18

16 Interconnection and Operating Agreement. Specific parameters shall include but are not limited to available transformer taps and short circuit withstand capabilities. D. Insulation Requirements Duke s standard requirements for equipment installed on the 100KV system shall meet the following minimum Basic Impulse Insulation Levels (BIL). BIL (kv) Open Air 550 Transformer 550 Winding Customer s Bus Lines shall have a minimum insulation level which will properly coordinate with the above referenced substation equipment. It is suggested that any line design utilized will have a minimum BIL of 550kV. E. Metering 1. Metering Equipment Requirements A solid state meter shall be used to measure the real and reactive power interchange between the Duke System and the Facility. All three bus lines will be metered separately at the interconnection point. 2. Meter Accuracy Meters shall be calibrated to 100% registration with a maximum deviation of +/- 0.5% accuracy at unity power factor for both full load and light load. These meters shall be calibrated to100% registration with a maximum deviation of +/- 1.0-% accuracy for 0.5 power factor at full load. 3. Instrument Transformers Potential devices and current transformers shall be 0.3% metering accuracy class for both magnitude and phase angle over the burden range of the installed metering circuit. Instrument transformer correction factors may be applied to the meter to adjust the meter for inaccuracies associated with the secondary burdens in the current transformer and voltage transformer circuits. It is determined that metering CTs will be utilized on the high side bushings of the GSUs. 4. Station Service Power Metering requirements for the plant auxiliary power will be determined on a case-by-case basis. Service to the plant auxiliary is considered to be a form of Retail Service and subject to various requirements as defined by the rate schedule selected for the particular service provided. Page 16 of 18

17 Appendix A Proposed One Line for Dan River Combined Cycle 100 KV Substation Proposed Electrical One Line Page 17 of 18

18 Page 18 of 18

19 Appendix B Interconnection Facilities Milestone Schedule Requirements Facility and Major Activity / Milestone Duration Months Prior to COD For Start of Activity Authorization To Proceed 22 Preliminary Engineering & Spec Development 2 22 Order of Long Lead Time Items 1 20 Detailed Engineering 3 19 Construction 9 16 Internal Acceptance Testing of Interconnection Facilities 1 7 Backfeed Facility (Interconnection In-service Date) 1 6 Merchant Facility Functional Testing 1 6 COD 0 Page 19 of 19